14 replies to this topic

[bloomers]

Model and Year : 1986 Mini City E

I have just taken my heater out, to replace the hoses with minispares blue silicone ones. When putting the heater back in, I may have put the hoses on the wrong way around? Is this possible, Is there a right and wrong way, for the hot water to enter and exit the heater?

Thank you. Ian

Edited by bloomers, 04 January 2009 - 12:36 AM.

[mini_mad69]

Did you top up the water afterwards?

Ben

[bloomers]

Yea, As i also replaced the radiator. Full to the top!

[mini_mad69]

You may need to run it for a bit, let the water circulate for a while and you may find that air will exit the system into the radiator and you will need to top it up again. Im not 100% sure but I wouldnt have thought it mattered which way the water flows through the matrix.

BEN

[bloomers]

Ok, Hopefully someone else can confirm this. I have run the system to bleed all the air out. And it goes warm to start, Then cold.

Cheers. Ian

[Dan]

It matters only in so much as if the hoses are plumbed in the right way it will produce hotter air. If you've got them the wrong way around it won't actually prevent it working. You have an air-lock in the heater, this is very common. Some poeple run the engine for 5 minutes with the rad cap off (and the engine cold obviously) and say that clears the blockage but personally I can't see any mechanism for how that would work. I just bleed it by releasing the heater inlet from the cylinder head or sandwich plate and letting coolant flow to the end of the hose before reconnecting.

By the way, the correct way to plumb it is for the hot water to run into the side of the matrix that is closest to the fan first and out of the side that is furthest from the fan before returning to the engine. It will be a few degrees hotter if it's plumbed like that, although some heater matrices don't allow that to happen because they don't really have two seperate cores that flow one after the other.

[bloomers]

Brilliant, Thanks for the help

Am I right in now thinking that the heater tap end is the exit flow of the hot water?

Ian

[jimbo1234567]

no your totally wrong

Edited by jimbo1234567, 04 January 2009 - 07:01 PM.

[bloomers]

ok, Helpful. Anyone else with a more worthy answer?

[Dan]

Well I've got a more accurate one.

Hot water runs from the engine into the heater from either the heater tap or elbow or (in later models) a sandwich plate under the thermostat. Return water from the heater returns to the radiator, running into the bottom hose. I think from what you asked that you had it the right way around, hopefully the above will make it clear.

[bloomers]

Brilliant Dan, Thank you very much for your help.

So manually fill the heater with coolant then connect back up?


Ian

Edited by bloomers, 04 January 2009 - 09:51 PM.

[Dan]

I disconnect the hose from the cylinder head, as this is the highest point. I don't do this with it running though because you need the coolant to flow the wrong way effectively. I disconnect it and plug the open end at the head with my thumb, then hold the hose lower then the rad and the air should be forced out. If the valve is on the head then once you are sure there is coolant present at the valve you can close it. You may need to give the bottom hose a squeeze or find some other way of forcing the air through. Topping it up while the hose is apart will help, you'll see the air bubble out.

Edited by Dan, 04 January 2009 - 09:56 PM.

[taffy1967]

Both times my heaters (on different Minis I've owned) have blown cold air once the fan was switched on, it was due to a faulty thermostat.

And this pdf will help tell you which was around the hoses should go on your heater: -

http://www.somerford.....20Cables .pdf

Edited by taffy1967, 04 January 2009 - 10:38 PM.

[bloomers]

Thank you for that link. I think I will change the thermostat as its an easy change...and when I had the head off for other faults, I think the Thermostate was damaged when trying to remove it, when the head was being stripped down.

Thank you everyone. I will let you know how I get on.

Ian

[unburntfuelinthemorning]